RGB Driver Electrical Characteristics

(R1, G1, B1, R2, G2, B2 outputs)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

R

DS-ON

ON Resistance

I = 75 mA

3.5

6

Ω

I

LEAKAGE

Off State Leakage Current

V

0.03

1

µA

I

MAX

Maximum Sink Current

(Note 5)

120

mA

T

SMAX

Maximum Slope Period

At Maximum Duty Setting

0.93

s

T

SMIN

Minimum Slope Period

At Maximum Duty Setting

31

ms

T

SRES

Slope Resolution

At Maximum Duty Setting

62

ms

T

START/STOP

Start/Stop Resolution

Cycle 1s

1/16

s

Duty

Duty Step Size

6.25

%

T

BLINK

Blinking Cycle Accuracy

−6

%

D

CYCF

Duty Cycle Range

FLASH_MODE = 1

0

99.6

%

D

CYC

Duty Cycle Range

FLASH_MODE = 0

0

33.2

%

D

RESF

Duty Resolution

FLASH_MODE=1(4 bit)

6.64

%

D

RES

Duty Resolution

FLASH_MODE=0(4 bit)

2.21

%

F

PWMF

PWM Frequency

FLASH_MODE = 1

20

kHz

F

PWM

PWM Frequency

FLASH_MODE = 0

6.67

kHz

RGB LED PWM Control (Note 15)

R1DUTY[3:0]

G1DUTY[3:0]

B1DUTY[3:0]

R2DUTY[3:0]

G2DUTY[3:0]

B2DUTY[3:0]

DUTY sets the brightness of the LED by adjusting the duty cycle of the PWM driver. The minimum duty

cycle is 0% [0000] and the maximum in the FLASH mode is

The peak pulse current is determined by the external resistor, LED voltage drop and the boost voltage. In

normal mode the maximum duty cycle is 33%.

R1SLOPE[3:0]

G1SLOPE[3:0]

B1SLOPE[3:0]

R2SLOPE[3:0]

G2SLOPE[3:0]

B2SLOPE[3:0]

SLOPE sets the turn-on and turn-off slopes. Fastest slope is set by [0000] and slowest by [1111]. SLOPE

changes the duty cycle at constant, programmable rate. For each slope setting the maximum slope time

appears at maximum DUTY setting. When DUTY is reduced, the slope time decreases proportionally. For

example, in case of maximum DUTY, the sloping time can be adjusted from 31 ms [0000] to 930 ms

[1111]. For 50% DUTY [0111] the sloping time is 14 ms [0000] to 434 ms [1111]. The blinking cycle has

no effect on SLOPE.

R1ON[3:0]

G1ON[3:0]

B1ON[3:0]

R2ON[3:0]

G2ON[3:0]

B2ON[3:0]

ON sets the beginning time of the turn-on slope. The on-time is relative to the selected blinking cycle

length. On-setting N (N = 0–15) sets the on-time to N/16 * cycle length.

R1OFF[3:0]

G1OFF[3:0]

B1OFF[3:0]

R2OFF[3:0]

G2OFF[3:0]

B2OFF[3:0]

OFF sets the beginning time of the turn-off slope. Off-time is relative to the blinking cycle length in the

same way as the on-time.

If ON=0,OFF=0 and RGB_PWM = 1, then RGB outputs are continuously on (no blinking), the DUTY

setting controls the brightness and the SLOPE setting is ignored.

If ON and OFF are the same, but not 0, the RGB outputs are turned off.

CYCLE[1:0]

CYCLE sets the blinking cycle: [00] for 0.25s, [01] for 0.5s, [10] for 1s and [11] for 2s. CYCLE effects to

all RGB LEDs.

www.national.com

13